Smallpox could be eradicated partly because

  1. the virus had stable antigens and no animal reservoir
  2. it had many antigen types
  3. antibiotics killed it
  4. it was a bacterium
Answer

A) the virus had stable antigens and no animal reservoir

One vaccine worked worldwide. AS & A Level Biology · Topic 11 Immunity · 11.2 Antibodies and vaccination

Biology MCQ · More A Level Biology: Immunity MCQs · Practise